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Port

A place where vessels may discharge or receive cargo; it may be the entire harbour including its approaches and anchorages, or only the commercial part of a harbour where the quays, wharves, facilities for transfer of cargo, docks, and repair shops are situated. Protection may be provided by natural or artificial features.

Substances that are essential for the growth of marine organisms that perform primary production (algae, bacteria, and plants). Excess nutrients, especially nitrogen and phosphorus, can be major pollutants.

A wave breaking on a shore or over a REEF, etc. Breakers may be classified into four types:

COLLAPSING--breaking occurs over lower half of wave, with minimal air pocket and usually no splash-up. Bubbles and foam present.

PLUNGING--crest curls over air pocket; breaking is usually with a crash. Smooth splash-up usually follows.

SPILLING--bubbles and turbulent water spill down front face of wave. The upper 25 percent of the front face may become vertical before breaking. Breaking generally occurs over quite a distance.

SURGING--wave peaks up, but bottom rushes forward from under wave, and wave slides up beach face with little or no bubble production. Water surface remains almost plane except where ripples may be produced on the beach face during runback.

An arbitrary division of a continuous scale of grain sizes such that each scale unit or grade may serve as a convenient class interval for conducting the analysis or for expressing the results of an analysis.